ITO, a typical transparent conductive film, is actively applied to a touch screen panel, OLED device, flexible device, etc., but it has a limit as a metal oxide to satisfy low sheet resistance and high flexibility which are required as substrates become enlarged, so an alternative material is urgently in need.
As an alternative material for solving the problem, a metal nanowire-based transparent conductive film is applied, and it has been used in various fields because it can achieve a low sheet resistance and have an excellent flexibility while maintaining high optical properties in films which are not achieved with ITO.
Unlike ITO, however, the metal nanowire-based-transparent conductive films have the disadvantage of a poor visibility when their patterning was conducted through an etching process. In the conventional ITO films, there were numerous efforts for adjusting high refractive index of ITO itself, but in the case of the metal nanowires, a haze by the light scattering reflected from the metal has been known as a factor which heavily affects the visibility, rather than the refractive index, and in fact, in the case of a silver nanowire, as the haze is distinguished from an etched portion and a non-etched portion, there is a problem that patterns are easily recognized to naked human eyes.
In the conventional transparent conductive films consisting of metal nanowires, patterns are formed through an etching process without any consideration of the visibility and there have been attempts to adjust the refractive index or haze properties of the etched surface and non-etched surface by forming an additional anti-reflection film on the etched surface or the rear surface of the etched surface, but in case that the anti-reflection film is formed with no distinction between the etched surface and the non-etched surface, it does not have a great effect on the visibility because the same anti-reflection effect is given to the non-etched surface as well.